Global Analysis - Annual 2004
Note: GHCN-M Data Notice
An omission in processing a correction algorithm led to some small errors on the Global Historical Climatology Network-Monthly dataset (GHCN-M v3.2.0). This led to small errors in the reported land surface temperatures in the October, November, December and Annual U.S. and global climate reports. On February 14, 2013, NCDC fixed this error in its software, included an additional improvement (described below), and implemented both changes as GHCN-M version 3.2.1. With this update to GHCN-M, the Merged Land and Ocean Surface Temperature dataset also is subsequently revised as MLOST version 3.5.3.
The net result of this new version of GHCN-M reveals very small changes in temperature and ranks. The 2012 U.S. temperature is 0.01°F higher than reported in early January, but still remains approximately 1.0°F warmer than the next warmest year, and approximately 3.25°F warmer than the 20th century average. The U.S. annual time series from version 3.2.1 is almost identical to the series from version 3.2.0 and that the 1895-2012 annual temperature trend remains 0.13°F/decade. The trend for certain calendar months changed more than others (discussed below). For the globe, ranks of individual years changed in some instances by a few positions, but global land temperature trends changed no more than 0.01°C/century for any month since 1880.
NCDC uses two correction processes to remove inhomogeneities associated with factors unrelated to climate such as changes in observer practices, instrumentation, and changes in station location and environment that have occurred through time. The first correction for time of observation changes in the United States was inadvertently disabled during late 2012. That algorithm provides for a physically based correction for observing time changes based on station history information. NCDC also routinely runs a .pairwise correction. algorithm that addresses such issues, but in an indirect manner. It successfully corrected for many of the time of observation issues, which minimized the effect of this processing omission.
The version 3.2.1 release also includes the use of updated data to improve quality control and correction processes of other U.S. stations and neighboring stations in Canada and Mexico.
Compared to analyses released in January 2013, the trend for certain calendar months has changed more than others. This effect is related to the seasonal nature of the reintroduced time-of-observation correction. Trends in U.S. winter temperature are higher while trends in summer temperatures are lower. For the globe, ranks of individual years changed in some instances by a few positions, but global temperature trends changed no more than 0.01°C/century for any month since 1880.
More complete information about this issue is available at this supplemental page.
NCDC will not update the static reports from October through December 2012 and the 2012 U.S and Global annual reports, but will use the current dataset (GHCN-M v. 3.2.1 and MLOST v. 3.5.3) for the January 2013 report and other comparisons to previous months and years.
PLEASE NOTE: The ranks and temperature anomalies in this report represent the values known at the time the report was issued. The actual ranks will change as subsequent years are added to the dataset. The anomalies themselves may change slightly as missing or erroneous data is resolved. Also, in 2009, NCDC switched to ERSST version 3b (from version 2) as a component of its global surface temperature dataset. Because the versions have slightly different methodologies, the calculated temperature anomalies will differ slightly. For more information about this switch please see the Global Surface Temperature Anomalies FAQ .
|Global temperatures in 2004 were 0.54°C (0.97°F) above the long-term (1880-2003) average**, ranking 2004 the fourth warmest year on record. The warmest year on record is 1998, having an anomaly of 0.63°C (1.13°F), followed by 2002 and 2003 both having an anomaly of 0.56°C (1.01°F). Land temperatures in 2004 were 0.83°C (1.50°F) above average, ranking fourth in the period of record while ocean temperatures were third warmest with 0.42°C (0.76°F) above the 1880-2003 mean.|
The map of temperature anomalies (above right) contains data
from an in-situ
and satellite blended data set of land and ocean temperatures.
The period of record for this data set is 1988-2004, a relatively
warm period compared to the base period used in the creation of the
map of temperature anomalies. Some minor differences in the
land surface anomalies between these two maps result from the
differences in base periods and data that are used to construct the
**The 1880-2003 average combined land and ocean annual temperature is 13.9°C (56.9°F), the annually averaged land temperature for the same period is 8.6°C (47.4°F), and the long-term annually averaged sea surface temperature is 16.1°C (60.9°F).
|Annual temperatures were above average across most land areas. The adjacent figure depicts warmer than average temperatures (for a 1961-1990 base period) that were widespread across much of the contiguous United States and Alaska, as well as most of Europe and Asia. Temperatures in these regions were 2-4°C (3.6-7.2°F) above the 1961-1990 average. This map was created using data from the Global Historical Climatology Network, a network of more than 7,000 land surface observing stations. The only widespread areas of negative anomalies were across western coastal areas of Australia, central Canada and north-central Siberia where temperatures were between 1 and 2°C (1.8-3.6°F) cooler than average.|
|Notable temperature extremes in 2004 included a severe heat
wave that affected much of eastern Australia from February until
the end of March. Many city and state temperature records were set
as maximum temperatures reached 45°C (113°F). According to
the Australian Bureau of Meteorology, the spatial and temporal
extent of the heat wave was greater than that of any other February
heat wave in the Australian meteorological record, and ranked
amongst the top five Australian heat waves in any month, just short
of the January 1939 event but comparable with those of January
2001, January 1982 and December 1972/January 1973. In Spain, during
June and July, 73-year records were broken when maximum
temperatures reached between 39-42°C (104-108°F). In Japan,
a heat wave during mid-July produced a record temperature of
39°C (103°F) in Tokyo's financial district, the hottest
temperature recorded since records began in 1923.
Early in the year, extreme cold temperatures as low as 0-5°C (32-41°F) in South Asia contributed to as many as 600 deaths from late December 2003 into January 2004. In July, cold temperatures were responsible for deaths of forty six children in Peru, along with more than 100,000 farm animals and 300,000 hectares (741,000 acres) of cropland destroyed. For more information on temperature extremes during 2004 see the annual report of Significant Events
|Global precipitation was above the 1961-1990 average in 2004, the first time in 4 years. Regionally drier than average conditions were widespread across the western U.S. where the multi-year drought continued to ravage the region. India monsoon rainfall was 87 percent of normal, with the worst regional deficit being in northwest India with 22 percent less than average precipitation. The March-May rainy season was shorter and drier than normal across parts of the Greater Horn of Africa, resulting in a continuation of multi-season drought in this region. In Kenya only 50 percent of normal rainfall has fallen in the past two years. In Somalia, more than 600,000 people were directly affected by the current drought and in need of food aid.|
|There were also areas of above average
precipitation in 2004. A winter storm brought heavy snowfall to
much of the Mediterranean and Middle East regions in January. The
storm blanketed areas with more than 61cm (2 feet) of snow causing
the closing of local airports, an avalanche and three deaths. In
Brazil, heavy rains that began in December and continued into
February caused floods and mudslides, leaving tens of thousands of
people homeless and killing at least 56 people. In April, a strong
storm system brought 127-178mm (5-7 inches) of rain to the
southwestern U.S. and adjacent areas in Mexico. Flash flooding of
the Escondido River in Piedras Negras caused 36 deaths and damaged
hundreds of homes. This event was characterized as some of the
worst flooding on record along the U.S.-Mexico border. For more
information about precipitation extremes during 2004, see the
annual report of Significant Events.
Additional information on other notable weather events can be found in the Significant Events section of this report.
Climatic Data Center is the world's largest active archive of
weather data. The preliminary temperature and precipitation
rankings are available from the center by calling: 828-271-4800.
NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts.